Moving heat exchange catheter system

ABSTRACT

A catheter system for controlling the body temperature of a patient by modifying the temperature of blood flowing within a blood vessel of the patient. The catheter system comprises a catheter body having a heat exchange region in contact with the blood; and a mechanism for moving the heat exchange surface, thereby increasing heat exchange between the heat exchange surface and blood flowing past the heat exchange surface. Various methods of moving the heat exchange surface are disclosed.

TECHNICAL FIELD

[0001] In general, the present invention relates to heat exchangecatheters adapted to control or modify a patient's internal bodytemperature, and in particular, intravascular heat exchange cathetersystems with heat exchange surfaces having a source of motion forgenerating sufficient motion to increase heat transfer between the heatexchange surface and the blood flowing past the heat exchange surface.

BACKGROUND OF THE INVENTION

[0002] Under ordinary circumstances, the thermoregulatory system of thehuman body maintains a near constant temperature of about 37° C. (98.6°F.), a temperature referred to as normothermia.

[0003] For various reasons, however, a person may develop a bodytemperature that is below normothermia, a condition known ashypothermia, or a temperature that is above normothermia, a conditionknown as hyperthermia. Hypothermia and hyperthermia are generallyharmful, and if severe, the patient is generally treated to reverse thecondition and return the patient to normothermia. Accidental hypothermiasignificant enough to require treatment may occur in patients exposed tooverwhelming cold stress in the environment or whose thermoregulatoryability has been lessened due to injury, illness or anesthesia. Forexample, this type of hypothermia sometimes occurs in patients sufferingfrom trauma or as a complication in patients undergoing surgery.Likewise, examples of hyperthermia include exposure to overwhelmingexposure to hot environmental stimulation, injury or illness, orcomplications of anesthesia.

[0004] However, in certain other situations hyperthermia and especiallyhypothermia may be desirable and may even be intentionally induced. Forinstance, hypothermia is generally recognized as being neuroprotective,and may, therefore, be induced in conjunction with treatments forischemic or hemorrhagic stroke, blood deprivation such as caused bycardiac arrest, intracerebral or intracranial hemorrhage, and head andspinal trauma. In each of these instances, damage to neural tissue mayoccur because of ischemia, increased intracranial pressure, edema orother processes, often resulting in a loss of cerebral function andpermanent neurological deficits.

[0005] Other examples where hypothermia may be neuroprotective includeperiods of cardiac arrest in myocardial infarction and heart surgery,neurosurgical procedures such as aneurysm repair surgeries, endovascularaneurysm repair procedures, spinal surgeries, procedures where thepatient is at risk for brain, cardiac or spinal ischemia such as beatingheart by-pass surgery or any surgery where the blood supply to theheart, brain or spinal cord may be temporarily interrupted.

[0006] Hypothermia has also been found to be advantageous as a treatmentto protect both neural tissue and cardiac muscle tissue during or aftera myocardial infract (MI).

[0007] Simple surface methods for warming, whether treating accidentalhypothermia or reversing hypothermia, include wrapping the patient inwarming blankets or immersing the patient in a warm water bath. If thehypothermia is not too severe, and the need to reverse the hypothermiais not to urgent, these methods may be sufficient. However, normalthermoregulatory responses such as vasoconstriction of capillary beds atthe surface of the body and arterio-venous shunting of blood away fromthe skin act to make the surface application of warmth very slow andinefficient.

[0008] Where hypothermia is desired, for example where a patient hassuffered a stroke, an attempt may be made to cool the patient byapplication of cooling blankets or alcohol rubs. These attempts toinduce hypothermia by application of surface cooling are slow andinefficient since the application of a cold blanket or cold alcohol tothe patient's skin will triggers these thermoregulatory responses.Furthermore, surface cooling will be extremely uncomfortable for anyawake patient. As an additional confounding factor, the patient is ofteninduced to shiver, greatly increasing the amount of heat generated bythe body, perhaps by a factor of five or more. This is and oftensufficient to make further reduction of patient temperature impossible.Shivering also markedly increases the discomfort of the patient,sometimes to the degree that continued surface cooling is not possible.

[0009] Sometimes warmed or cooled breathing gases or warm infusions areapplied to heat or cool a patient. These are also slow and poorlycontrolled since the amount of heat that can be added or removed islimited by the amount of infusate and the limitations on the temperatureof the gas or infusate that can be used without harming the patient.

[0010] A very invasive method of controlling the temperature of apatient is sometimes employed in which the patient's blood is shuntedthrough a cannula (attached to a vein such as the inferior vena cava) toan external pump, and then pumped back into the patient's body. Theblood removed from the patient is heated or cooled externally before itis reintroduced into the patient's body. An example of such a by-passarrangement is the Cardio-Pulmonary By-pass system (CPB) often used inopen heart surgery. This by-pass method, once it is initiated, is bothfast and effective in adding or removing heat from a patient's blood andin exercising control over the patient's body temperature in general,but has the disadvantage of involving a very invasive medical procedurewhich requires the use of complex equipment, a team of highly skilledoperators, is generally only available in a surgical setting, andbecause of these complexities, is extremely expensive and requires along time to initiate. In fact, it generally cannot begin until afterthe patient's thorax has been surgically opened, cannot re-warm afterthe thorax is closed. Furthermore, such a by-pass method also involvesmechanical pumping of blood, which is generally very destructive to theblood resulting for example in hemolysis. For this last reason, use ofby-pass for more than four hours is generally considered undesirablewhich limits the use of this technique for lengthy temperature control.

[0011] Another method for adding or removing heat that does not involvepumping the blood with an external, mechanical pump include a method oftreating or inducing hypothermia or hyperthermia by means of a heatexchange catheter placed in the bloodstream of a patient was describedin U.S. Pat. No. 5,486,208 to Ginsburg, the complete disclosure of whichis incorporated herein by reference. The Ginsburg patent discloses amethod of controlling the temperature of a body by adding or removingheat to the blood by inserting a heat exchange catheter having a heatexchange region into the vascular system and exchanging heat between theheat exchange region and the blood to affect the temperature of apatient. One method disclosed for doing so includes inserting a catheterhaving a heat exchange region comprising a balloon into the vasculatureof a patient and circulating warm or cold heat exchange fluid throughthe balloon while the balloon is in contact with the blood.

[0012] In general, the transfer of heat between the heat exchange regionof such a catheter and the flowing blood may be expressed by thefollowing formula:

Q=USΔT

[0013] where Q is the heat transfer rate in watts, U is overall heattransfer coefficient, S is the surface area of the interface between theheat exchange region and the flowing blood, and ΔT is the temperaturedifference between the flowing blood and the heat exchange region. Inorder to maximize the speed and control of heat transfer between theheat exchange catheter described below and the blood of a patient, theheat transfer rate (Q) must be maximized.

[0014] However, for a given heat exchange catheter, for example thecatheter described in the Detailed Description below, the surface areaof contact between the heat exchange region and the blood (S) is fixed.

[0015] For heat exchange between the catheter and the blood, the ΔT isalso limited. The blood is generally the same temperature of the body,between 37° C. and 32° C. The heat exchange region cannot be maintainedmuch below 0° C. or it will freeze the blood in contact with the heatexchange region. Any temperature above about 50° C. is generallyconsidered harmful to the blood, so the heat exchange region generallywill not be maintained at a temperature significantly below 0° C. orabove 50° C.

[0016] The variable U is determined by a number of different variablesincluding the material of the heat exchange catheter, the material ofthe flowing fluid (blood) the rate of flow, and the like. For a givenheat exchange catheter in the blood, the material of the catheter isfixed, and the heat exchange nature of the blood and the rate of bloodflow are generally not within the control of the physician. With allthese parameters fixed or limited, it would be extremely advantageous todevise a way to further enhance heat transfer where the above conditionsexist. This invention makes possible such an enhancement.

SUMMARY OF THE INVENTION

[0017] The present invention provides a catheter system for controllingthe body temperature of a patient by modifying the temperature of bloodflowing within a blood vessel of the patient. The present systemcomprises a catheter body having a heat exchange region, the heatexchange region having a heat exchange surface in contact with theblood; and a source of motion connected, directly or indirectly, to theheat exchange region so as to impart motion to the heat exchange surfacewhile the heat exchange surface is in contact with blood flowingthereover sufficient to induce gentle mixing of the blood as it flowsover the heat exchange surface.

[0018] In accordance with the present invention, movement of the heatexchange surface (i.e.: the surface of the heat exchange region which isdisposed in contact with the blood flowing thereover) enhances heatexchange between the catheter system and the blood flow. Specifically,such movement of the heat exchange surface disrupts smooth fluid flowover the heat exchange surface, thereby causing mixing of the blood, forexample, stirring or eddies in the blood passing thereover, sufficientto enhance the heat exchange between the flowing blood and the heatexchange surface.

[0019] The present invention thus provides methods for treating orinducing hypothermia or hyperthermia by inserting the present catheterbody (either with a catheter shaft attached to or having as an integralpart, a moving heat exchange surface) into a blood vessel of the patientand selectively transferring heat either to or from the blood flowingthrough the vessel. It enhances the ability to exchange heat, therebyenhancing both the ability to induce or treat hypothermia orhyperthermia and the ability to rapidly and precisely control the bodytemperature of the patient.

[0020] In the various aspects of the invention in which a fluid filledheat exchange balloon is used, movement of the heat exchange surface ofthe balloon also beneficially disrupts fluid flow within the balloon,and specifically adjacent the interior of the heat exchange surface,thereby causing stirring or eddies in the heat exchange fluid passingtherethrough, thereby enhancing the heat exchange between the heatexchange fluid and the heat exchange surface. In preferred aspects, theheat transfer balloon may be a multi-lobed, multi-lumen balloon. Inaccordance with the present invention, movement of the heat exchangesurface is induced by a source of motion connected, directly orindirectly, to the heat exchange region. In various aspects of theinvention, this source of motion comprises a wire extendinglongitudinally through at least a portion of the catheter body and atransducer adapted to move the wire, in some instances in the ultrasonicrange.

[0021] Alternatively, systems are also provided to cause motion of theheat exchange surface by providing a source of motion comprises a wireextending longitudinally through at least a portion of the catheter bodyand mechanisms to rotate the wire, wherein at least a portion of thewire has a non-symmetric cross section or a radial protrusion extendingtherefrom. In addition, systems having bent wires, which when rotatedcause a distal end of the catheter to move in a stirring motion are alsoprovided. Alternatively, in the case of a fluid filled heat exchangeballoon, the movement may be induced or supplemented in the heatexchange surface of the balloon by a source of motion which introducesmovement into the fluid column of the heat exchange fluid passingtherethrough.

[0022] Yet another source of motion may be provided by a fluid flowdeflecting vane or like structure on the catheter body, on the heatexchange region, or on a guide wire passed through at least a portion ofthe catheter into the flowing bloodstream. The flowing blood deflectsagainst the vane, causing motion of the heat exchange region.

[0023] Accordingly, the present invention provides a variety ofdifferent mechanisms which may optionally be used to cause movement ofthe heat exchange surface of the catheter body, which preferably causesgentle mixing motion of the blood passing over the heat exchange surfaceof the catheter. Such mixing (by causing stirring or eddy formation inthe fluid flow) has the beneficial effect of increasing heat transferbetween the heat exchange region of the catheter and the blood flowingover the catheter. Depending on the characteristics of the fluids, theheat exchange surface, and the temperatures involved, this may increaseheat exchange by 25% or more compared to a non-moving heat exchangesurface. Accordingly, the present invention provides systems to rapidly,efficiently and controllably exchanging heat with the blood of a patientso the temperature of the patient or target tissue within the patientcan more effectively and rapidly be altered, or maintained at sometarget temperature.

[0024] The present invention further provides a method of controllingthe body temperature of a patient by modifying the temperature of bloodflowing within a blood vessel of the patient. These methods preferablycomprise advancing a catheter body having a heat exchange surface intothe patient's blood vessel such that the heat exchange surface is incontact with the patient's blood; causing the temperature of the heatexchange surface to be different from that of the blood such that heattransfer occurs between the heat exchange surface and the patient'sblood; and moving the heat exchange surface of the heat exchange region,thereby disrupting the fluid flow over the heat exchange surface of theheat exchange region of the catheter body. In addition, such movement ofthe heat exchange surface may also disrupt fluid flow within the heatexchange region of the catheter itself, for example, along the interiorof the heat exchange surface in the case of a fluid filled heat exchangecatheter. Accordingly, in optional aspects, the movement is imparteddirectly to the fluid column of heat exchange fluid passing through thecatheter.

[0025] In various aspects of this method, different techniques may beused to cause movement of the catheter body, including ultrasoundapplication to a wire running along through at least a portion of thecatheter body. Rotation of a wire extending longitudinally through thecatheter body (with the wire having either a non-symmetric crosssection, a bend, or a number of bends therein, or a radial protrusionextending therefrom) may also be used. When such a wire is rotated, itwill cause the heat exchange surface of the heat exchange region tomove.

[0026] As used herein, “movement” of the present heat exchange surfaceof the heat exchange region of the catheter body comprises moving atleast a portion of the heat exchange surface such that at least aportion of the catheter body deflects in various radial directionsrelative to the flow of the blood in the vessel, (i.e.: directionsperpendicular to the central longitudinal axis of the catheter in theblood vessel), with the catheter body also preferably moving in variousradial directions, in either a serpentine or stirring motion.

[0027] In additional aspects, “movement” of the heat exchange surfacemay also encompass movement of a portion of the catheter body back andforth in an axial direction, i.e.: along the central longitudinal axisof the catheter body, or rotational motion, i.e. rotation of anon-smooth heat exchange surface around the central longitudinal axis ofthe catheter body, or any combination of these various motions.

[0028] In addition, in the case of a fluid filled heat exchange balloon,the movement of the heat exchange surface of the balloon may be inducedor supplemented by a source of motion which introduces movement into thefluid column of the heat exchange fluid passing therethrough.

BRIEF DESCRIPTION OF THE DRAWINGS

[0029]FIG. 1 is an illustration of a catheter having a longitudinallyextending wire passing therealong, with an ultrasound transducer mountedto move the wire in a radial direction.

[0030]FIG. 2 is an illustration of a catheter having a longitudinallyextending wire passing therealong, with an ultrasound transducer mountedto move the wire in an axial direction.

[0031]FIG. 3 is an illustration of a catheter having a longitudinallyextending wire passing therealong, the wire being bent at one location.

[0032]FIG. 4 is an illustration of a catheter having a longitudinallyextending wire passing therealong, the wire having a protrusionextending radially therefrom.

[0033]FIG. 5 is a sectional end view of a catheter having alongitudinally extending wire passing therealong, the wire having anon-symmetrical cross section.

[0034]FIG. 6 illustrates a distal end view of the present cathetersystem, showing various radial directions.

[0035]FIG. 7 illustrates a catheter with a multilobed balloon heatexchange region attached to the distal end of the catheter body and witha guide wire therethrough having several bends on the guide wire.

[0036]FIG. 8 illustrates a catheter with flow deflecting vanes andhaving a guide wire therethrough having a flow deflecting vane on thedistal end of said guide wire.

[0037]FIG. 9A illustrates a heat exchange catheter having a deflectingwire therein.

[0038]FIG. 9B illustrates a heat exchange catheter having a deflectingwire therein, said deflecting wire in the retracted position.

[0039]FIG. 10 shows a heat exchange catheter with a rotating heatexchange surface.

DESCRIPTION OF THE SPECIFIC EMBODIMENTS

[0040] The present invention provides apparatus and methods forcontrolling the body temperature of a patient by modifying thetemperature of blood flowing within a blood vessel of the patient. Inpreferred aspects, the present invention provides a catheter body havinga heat exchange region disposed in contact with the blood, and a systemfor moving the heat exchange surface of the heat exchange region of thecatheter body, thereby breaking up or disrupting fluid flow thereover,by stirring and by causing eddy formation in blood flowing over a heatexchange surface of the heat exchange region of the catheter body.

[0041] A variety of different catheter bodies and a variety of differentsources of motion, including, but not limited to those described hereinas examples, may be used to cause the heat exchange surface of the heatexchange region of the catheter body to move. In various aspects, theactual column of heat exchange fluid passing through a heat exchangeballoon may also move, as will be explained.

[0042] Accordingly, by way of example, FIGS. 1 to 6 illustrate variousapproaches to causing a heat exchange surface of a catheter to “move”,in accordance with the present invention.

[0043] Referring first to FIG. 1, a heat exchange catheter body 10 isprovided. Catheter body 10 may comprise any type of heat exchangecatheter. For example, catheter body 10 may comprise a fluid filledballoon heat exchange catheter (as illustrated in FIG. 6) or a heatexchange catheter having resistance heaters disposed therein (asillustrated in FIG. 1). Suitable examples of heat exchange cathetersystems which may comprise the present catheter body 10 are also foundin various U.S. patents.

[0044] It is to be understood that the present invention may be adaptedfor use with a wide variety of different temperature regulating cathetersystems. For example, in accordance with the present invention, thecatheter system used may comprise a catheter system adapted for warmingthe body fluid passing thereover (for example, a system having anelectric heater disposed therein, or alternatively, a system pumping aheat exchange fluid therethrough). In addition, the catheter system usedmay comprise a catheter system adapted for cooling the body fluidpassing thereover (for example, a system pumping a cooled fluid flowtherethrough).

[0045] In the embodiment of the invention shown in FIG. 1, catheter body10 comprises a heat exchange region 11 in which a resistance heater 13is disposed. In this aspect, surface 12 comprises the heat exchangesurface.

[0046] In accordance with the present invention, movement of a heatexchange surface is induced by a source of motion.

[0047] In various aspects of the invention, this source of motioncomprises a wire extending longitudinally through at least a portion ofthe catheter body and a transducer adapted to move the wire. Forexample, catheter body 10 has a longitudinally extending wire 20 passingthrough at least a portion thereof, and a transducer 22 mounted therein.

[0048] In accordance with the present invention, the source of motion isconnected to the heat exchange region so as to impart movement to theheat exchange surface. This may be accomplished by a number of differentapproaches, including, but not limited to the examples set out below.

[0049] Returning to FIG. 1, transducer 22 may be attached to wire 20 tocause wire 20 to move. Transducer 22 preferably comprises an ultrasoundtransducer, but need not be so.

[0050] In one preferred aspect, transducer 22 is preferably positionedin contact with wire 20 such that it moves the proximal end 21 of wire20 back and forth in radial directions R1.

[0051] In this aspect of the invention, vibrational energy passes (aswaves) along wire 20 from its proximal end 21 to its distal end 23 suchthat catheter 20 moves. In this aspect, the movement of wire 20 (andcatheter 10) will be substantially in radial direction R1, causing thecatheter to “wag” in a two dimensional plane (i.e.: in the plane of thepage on which FIG. 1 is illustrated, see also direction R1 in FIG. 6 asexplained below).

[0052] As such, movement of catheter body 10 by transducer 22 results ina movement being directly transmitted along at least a portion of thelength of catheter body 10, thereby causing heat exchange surface 12 ofheat exchange region 11 of catheter body 10 to move.

[0053] Alternatively, however, transducer 22 may instead be connected toproximal end 21 of wire 20 such that wire 20 “shakes” or “trembles”,i.e. moving in 3 dimensions (e.g.: R1, R2 and R3 as illustrated in FIG.6 as explained below), such that movement of wire 20 is not limited tomovement within the plane of the page on which FIG. 1 is illustrated.Accordingly, it is to be understood that the system shown in FIG. 1 maybe adapted for vibrational movement in either of these two or threedimensional modes, depending upon how transducer 22 is coupled withproximal end 21 of wire 20.

[0054]FIG. 6 illustrates an end view of the present catheter system(with catheter 10 and wire 20 straightened such that wire 20 isco-linear with a central longitudinal axis extending through catheter10), showing various radial directions. Back and forth movement whichonly occurs in radial directions R1 constitutes (2 dimensional )movement in one preferred plane. In contrast, movement which occurs inall of radial directions R1, R2 and R3 (and in all radial directions atangles therebetween) constitutes three dimensional movement.

[0055] In the present invention, “movement” of the heat exchange surfacemay also be accomplished by repeatedly deflecting at least a portion ofthe catheter body in various radially outward directions (i.e.:directions perpendicular to the central longitudinal axis of thecatheter). In accordance with the present invention, such radialdeflection thus may thus result in a “serpentine” movement of theportion of the catheter body which comprises heat exchange surface 12.This is distinguished from a simple “pulsing” movement in which thecentral longitudinal axis of the catheter body would instead remain atthe same position, for example, with a heat surface of a fluid filledheat exchange balloon simply moving radially inwards and outwards, withthe balloon inflating (i.e.: with its heat exchange surface movingoutwardly from the center of the catheter body) and deflating (i.e.:with its heat exchange surface moving inwardly toward the center of thecatheter body).

[0056] In accordance with the present invention, however, the movementresulting from at least a portion of the catheter body repeatedlydeflecting in various radially outward R1 directions comprises movementof the catheter body back and forth in two opposing radial directions(i.e.: with the catheter body “wagging” in a preferred plane).Alternatively, however, such movement may result in at least a portionof the catheter body repeatedly deflecting in more than two opposing R1,R2 and R3 radial directions with at least a portion of catheter body 10either: (1) “shaking” or “trembling” such that a central axis of thecatheter body moves in various random radial directions over time or,(2) a portion of catheter body 10 rotates around the centrallongitudinal axis extending through a remaining portion of the catheter.

[0057] In the “shaking” or “trembling” aspect, the central axis of thecatheter body (which is shown in FIG. 6 as being co-linear with wire 20)will preferably tend to return to a central position over time.

[0058] Returning to FIG. 1, the frequency of movement of heat exchangesurface 11 of catheter body 10 may be in an ultrasonic range, but neednot be so. For example, movement at a frequency below the ultrasonicrange is also contemplated. In this lower frequency aspect of theinvention, the present catheter body may simply move gently at an easilyvisible frequency, for example one or two cycles per second. Theamplitude (i.e. the radial distance in direction R to which the “moving”heat exchange region moves) may be greater at lower frequencies, but inany event, it will be constrained by the width of the blood vessel inwhich the heat exchange region is located. Therefore, some axial motionmay as well may be induced in order to disrupt the layered flow of bloodover the heat exchange region.

[0059] Modification to this design is also possible. For example,transducer 22 may instead be coupled to distal end 23 of wire 20, withvibratory motion moving from distal end 23 to proximal end 21 of thewire.

[0060] Referring next to FIG. 2, heat exchange catheter body 10 is againprovided. Catheter body 10 has a longitudinally extending wire 20passing therealong, and a transducer 22A mounted therein. In thisaspect, transducer 22A is positioned in contact with wire 20 such thatit moves the proximal end of wire 20 back and forth in axial directionA. In this aspect of the invention, distal end 23 of wire 20 ispreferably attached to the distal end of the catheter. In this aspect ofthe invention, vibrational energy passes along wire 20 from its proximalend 21 to its distal end 23 (with portions of wire 20 alternatinglybeing in tension and compression) such that catheter 20 moves. In thisaspect, the movement of catheter 20 will be substantially in axialdirection A.

[0061] Referring next to FIG. 3, the source of motion may also comprisea wire extending longitudinally through at least a portion of thecatheter body with a mechanism adapted to rotate the wire. In oneaspect, a distal portion of the catheter body rotates around a centrallongitudinal axis A1 extending generally through catheter body 10, asfollows.

[0062] Heat exchange catheter body 10 is provided. Catheter body 10 hasa longitudinally extending wire 20 passing therethrough. Wire 20 isslightly bent at kink or bend 25 (the angle of which is exaggerated inFIG. 3 for clarity of illustration). Proximal end 21 of wire 20 isattached to rotation system 30 (which preferably comprises a motor).Rotation system 30 rotates wire 20 about axis A1-A1 such that the distalend 15 of catheter 10 (and distal end 23 of wire 20) rotate about axisA1-A1, with distal end 15 moving in a “stirring” motion, being disposedat roughly the same radial distance form axis A1-A1. As such, variousportions along length 17 of catheter body 10 will preferably remain atthe same distances from the central longitudinal axis A1-A1 of thecatheter as wire 20 is rotated.

[0063] Axis A1-A1 preferably is co-linear with the central longitudinalaxis of the catheter when the catheter is fully straightened out. As canbe seen in FIG. 3, a large (proximal) portion of the catheter may remainco-linear with axis A1-A1, such that catheter body movement is insteadgenerally limited to movement in a distal region of the catheter(comprising the heat exchange region).

[0064] In various optional aspects, wire 20 may have more than one bendtherealong. Together, these multiple bends may position distal end 15 ofcatheter 10 such that it is not co-axial with axis A1-A1. For example,in another aspect as shown in FIG. 7, wire 20 may have a plurality ofbends therealong which taken together position distal end 15 of catheterbody 10 co-axial with axis A1-A1. In this aspect of the invention,distal end 15 of catheter body 10 will remain disposed on axis A1-A1while wire 20 is rotated. However, body portions 10A and 10B wouldpreferably extend in opposing radial directions R1. When wire 20 isrotated, relative movement of body portions 10A and 10B would tend todisrupt fluid flow passing over catheter 10.

[0065] In alternate aspects, movement may be caused by a non-symmetricalcross section (or radial protrusion) disposed at a distal end of thewire such that, as the wire is rotated, the distal end of the catheterwill circle around a central longitudinal axis extending through themajority of the length of the catheter body (with the distal end of thecatheter tending to remain at the same distance from this centrallongitudinal axis), as follows.

[0066] Referring next to FIG. 4, heat exchange catheter body 10 isprovided. Catheter body 10 has a longitudinally extending wire 20passing therethrough. Wire 20 has a protrusion 27 extending radiallytherefrom. Proximal end 21 of wire 20 is attached to rotation system 30(which preferably comprises a motor). Rotation system 30 rotates wire 20about axis A1-A1 such that protrusion 27 also rotates about axis A1-A1such that distal end 15 of catheter body 10 (and distal end 23 of wire20) is caused to rotate about axis A1-A1, causing at least the distalportion of catheter body 10 to move.

[0067] Referring next to FIG. 5, heat exchange catheter body 10 isprovided. Catheter body 10 has a longitudinally extending wire 20Apassing therethrough. Wire 20 has at least a portion of which has anon-symmetrical cross section. Wire 20 is rotated about axis A1-A1 (forexample, by a rotation system identical or similar to rotation system 30of FIGS. 3 and 4). Since wire 20A is non-symmetrical in cross section,rotation of wire 20A will cause catheter body 10 to move. Wire 20A mayoptionally have a non-symmetrical cross section along its entire length,or only along a small portion of its length. When the nonsymmetricalportion of wire 20A is disposed near its distal end 23, rotation of wire20A causes the distal end of catheter body 10 to rotate about axisA1-A1, causing heat exchange surface 12 catheter body 10 to move.

[0068] Referring again to FIG. 7, in which the heat exchange regioncomprises a fluid filled balloon, such a balloon may be a simple singlelumen balloon, or may comprise a multi-lumen, multi-lobbed balloon. Thecatheter body in this instance comprises a shaft portion 51 and amulti-lobed balloon 55 attached to the distal end of the catheter shaft.The heat exchange region may also be formed integral with the shaft, aswas the case in the embodiments previously discussed. In these systems,the heat exchange surface of the heat exchange region comprises thesurface of a heat exchange balloon. In such systems, heat exchangeoccurs between both the heat exchange fluid and the balloon surface, andalso between the balloon surface and the blood flowing thereover. Whenusing a multi-lumen, multi-lobbed balloon, the various lobes of theballoon may preferably wrapped or braided around a central lumen, asshown.

[0069] In a supplemental aspect of the invention, where the catheterexchanges heat with the blood by means of circulating a heat exchangefluid through the heat exchange region of the catheter, movement mayalso be imparted to the heat exchange region by introducing a movementinto the fluid column circulating through the heat exchange region. Thismay be done, for example, by attaching an ultrasound movement generatorto the hub of the catheter to impart the movement to the fluid column.

[0070] Such movement of a fluid column of heat exchange fluid isdistinguished from existing systems which simply pulse fluid through aheat exchange balloon, i.e. inflating and deflating a balloon to thedegree necessary to prevent blood clot formation. In contrast, thepresent system can induce movement in the fluid column without simplyexpanding and contracting the outer balloon diameter to the degree ofthe prior art.

[0071] Where heat exchange is occurring between two flowing fluids, itis most efficient to have counter-current flow. That is, the flow of theheat exchange liquid is counter to the flow direction of the fluid withwhich it is exchanging heat. Since a heat exchange catheter might beinserted into blood vessels in various ways which would result in thenatural blood flowing being different in different instances (i.e.proximal to distal, or distal to proximal), the present catheter mayoptionally be advantageously constructed such that the direction of thefluid flow in the portion of the heat exchange region exposed to theflow of the body fluid could be adjusted to flow in either direction topermit the catheter could be inserted into the blood vessel in eitherdirection, with the direction of the flow of the heat exchange fluidadjusted to flow counter to the flow in the vessel.

[0072] In another aspect of the invention, as illustrated in FIG. 8, thesource of motion is a flow deflecting vane that is deployed in theflowing bloodstream within the vessel. The flow deflecting vane may beon the catheter shaft 50 or may be located directly on the heat exchangeregion of the catheter 52. Alternatively, it may be located on a guidewire, for example on the distal end of a guide wire 54, that is passedthrough at least a portion of the catheter body and out into thebloodstream. The flow deflecting vane, wherever located in the flowingblood, moves about in the bloodstream and thereby imparts motion to theheat exchange region.

[0073] Although the illustration shows flow deflecting vanes on allthree locations, it will be understood by those of skill in the art thata single flow deflecting vane, or several flow deflecting vanes on asingle structure, or any combination may be utilized and the cathetersystem will still be within the contemplation of this invention.Likewise, the flow deflecting vane may be a rigid structure protrudingfrom a portion of the catheter or from the guide wire, or may be thestructural contour of the heat exchange region, shaft, or guide wiredesigned to introduce motion when deployed in a flowing bloodstream. Forexample, if the surface of a multi-lobed heat exchange balloon hasasymmetrical protrusions that induce motion, this is within thecontemplation of this invention. Likewise, although a guide wire wasused in this illustration, a similar wire structure such as atemperature probe extending from the catheter might be configured toinduce motion and that too would be within the contemplation of thisinvention.

[0074] Another system for imparting motion to the heat exchange surfacecomprises a pull wire and a source of variable tension on the pull wirefor alternatively pulling and releasing the wire. Such a system is shownin FIGS. 9A and 9B. A catheter having a heat exchange surface 70 has apull wire 72 extending therethrough to an attachment location 74 nearthe heat exchange region of the catheter. A source of tension, forexample a source of reciprocal motion 76 is attached to the pull wire.The attachment location is asymmetrical, for example on one side of acircular lumen, so that when the wire is pulled, the heat exchangesurface is curved in a radial direction, and when the wire is pushed orrelaxed, the heat exchange surface is relatively straight along thecatheter axis. By repeatedly pulling and then relaxing the pull wire,the heat exchange surface is moved within the flowing bloodstream so asto enhance heat exchange.

[0075] Rotational motion of the heat exchange surface, where the surfacehas features that may act to stir the flowing fluid, will also enhanceheat exchange. For example, in FIG. 10, a catheter has an inflow lumen80 and a coaxial heat exchange region 82. A fluid tight bearing 84 islocated between the proximal catheter body 86 and the heat exchangeregion. The surface of the heat exchange region is formed with a seriesof protrusions 88 such as flow deflecting vanes. In this case, the bloodflow over the surface would impart rotational motion as indicated byarrows 90 of the heat exchange region, which would rotate relative tothe catheter shaft 86. The bearing 84 would permit the rotation whilemaintaining the fluid tight seal so that heat exchange fluid indicatedby the arrows 92 could flow down the inflow lumen 80, into the interiorlumen of the heat exchange region 94 and back down the outflow lumen 96.A working lumen 98 could also be present in such a catheter, with theworking lumen located down the center of the inflow lumen 80. Theworking lumen may extend distal of the heat exchange region. If so, abearing may exist where the working lumen exits the heat exchange region100. Alternatively, that location may be a point of attachment, so thatrotation of the working lumen serves to rotate the heat exchange region.A source of rotation motion attached to the proximal end of the workinglumen, for example outside the patient, could thus serve to impartrotational motion to the heat exchange surface.

[0076] The embodiments set forth herein are merely exemplary of systemsoperating in accordance with the present invention. Such exemplaryembodiments are not limiting. Rather, it is to be understood that thepresent invention encompasses all systems set forth in accordance withthe attached claims, and those modifications which would be apparent toone skilled in the art.

What is claimed is:
 1. A catheter system for controlling bodytemperature of a patient by modifying the temperature of blood flowingwithin a blood vessel of the patient, the System comprising: a catheterbody having a heat exchange region, the heat exchange region having aheat exchange surface in contact with the blood; and a source of motionconnected to the heat exchange region so as to impart movement to theheat exchange surface while the heat exchange surface is in contact withblood flowing thereover.
 2. The system of claim 1 wherein the catheterbody comprises a catheter shaft and a heat exchange region, said heatexchange region attached to the distal end of said shaft.
 3. The systemof claim 1 wherein the heat exchange region is integral with saidcatheter shaft.
 4. The system of claim 1 where the source of motion isconnected indirectly to the heat exchange region.
 5. The system of claim1 wherein the source of motion is directly attached to the catheter bodyso as to impart motion to the heat exchange region.
 6. The system ofclaim 1 wherein the source of motion is a flow deflecting vane attachedto the catheter body and placed in a flowing stream of fluid.
 7. Thesystem of claim 1, wherein the source of motion comprises: a wireextending longitudinally through a portion of the catheter body; and atransducer connected to the wire, the transducer adapted to move thewire.
 8. The system of claim 2, wherein the transducer comprises anultrasound transducer.
 9. The system of claim 2, wherein the transduceris attached to a proximal end of the wire.
 10. The system of claim 4,wherein the transducer is adapted to move the wire in a radialdirection.
 11. The system of claim 4, wherein the transducer is adaptedto move the wire in an axial direction.
 12. The system of claim 1,wherein the source of motion comprises: a wire extending longitudinallythrough a portion of the catheter body, at least a portion of the wirehaving a non-symmetrical cross section; and a mechanism for rotating thewire.
 13. The system of claim 7, wherein the portion of the wire havinga non-symmetrical cross portion is disposed at a distal end of the wire.14. The system of claim 1, wherein the source of motion comprises: awire extending longitudinally through a portion of the catheter body; aprotrusion extending from one side of the wire; and a mechanism forrotating the wire.
 15. The system of claim 9, wherein the protrusionextending from one side of the wire is disposed at a distal end of thewire.
 16. The system of claim 1, wherein the source of motion comprises:a wire extending longitudinally through a portion of the catheter body,the wire being angled such that a portion of the wire is deflected in aradial direction; and a mechanism for rotating the wire.
 17. The systemof claim 1, wherein the heat exchange surface comprises: an outersurface of a fluid filled heat exchange balloon.
 18. The system of claim17 wherein the source of motion is alternating inflation and deflationof the balloon.
 19. The system of claim 18 wherein the balloon iselastomeric.
 20. The system of claim 18 wherein the balloon isnon-compliant.
 21. The system of claim 18 wherein the balloon motioncomprises partial inflation and partial deflation.
 22. The system ofclaim 12, wherein the fluid filled heat exchange balloon comprises amulti-lobed balloon.
 23. The system of claim 1, wherein the heatexchange surface comprises a plurality of heat-transfer fins extendingfrom the catheter body.
 24. The system of claim 1, wherein the heatexchange surface comprises an internal heating system disposed withinthe catheter body.
 25. The system of claim 15, wherein the internalheating system comprises a resistance heater.
 26. The system of claim15, further comprising a pumping system for passing heat exchange fluidthrough the catheter body, the heat exchange fluid being at a differenttemperature than the blood flowing in the blood vessel.
 27. The systemof claim 15, further comprising a temperature sensor disposed within thecatheter body.
 28. A system as in claim 1 wherein said source of motionis a flow deflecting vane extending from said heat exchange surface. 29.A system as in claim 1 wherein said source of motion is a flowdeflecting vane extending from said catheter body proximal of said heatexchange surface.
 30. A system as in claim 1 wherein said source ofmotion is a flow deflecting vane extending from said catheter bodydistal of said heat exchange surface.
 31. A system as in claim 1 whereinsaid source of motion is a guide wire extending at least partiallythrough said catheter body and exiting said catheter body into saidflowing blood, the portion of said guide wire located in said flowingblood having a flow deflecting vane formed thereon.
 32. A method ofcontrolling the body temperature of a patient by modifying thetemperature of blood flowing within a blood vessel of the patient, themethod comprising: advancing a catheter body having a heat exchangeregion into the patient's blood vessel such that a heat exchange surfaceis in contact with the patient's blood; causing the temperature of theheat exchange region to be different from that of the blood such thatheat transfer occurs across the heat exchange surface between the heatexchange region and the patient's blood; and moving the heat exchangesurface, thereby disrupting flow of the blood over the heat exchangesurface and enhancing heat exchange between the heat exchange surfaceand the flowing blood.
 33. The method of claim 19, wherein causingdeflection of at least a portion of the catheter body occurs in radialdirections, thereby disrupting fluid flow over a surface of the heatexchange region of the catheter body.
 34. The method of claim 19,wherein causing the temperature of the heat exchange region to bedifferent from that of the blood comprises increasing the temperature ofthe heat exchange region relative to the temperature of the blood. 35.The method of claim 19, wherein causing the temperature of the heatexchange region to be different from that of the blood comprisesdecreasing the temperature of the heat exchange region relative to thetemperature of the blood.
 36. The method of claim 19, wherein causingthe temperature of the heat exchange region to be different from that ofthe blood comprises circulating heat exchange fluid across one side ofthe heat exchange surface.
 37. The method of claim 19, wherein movingthe heat exchange surface comprises moving a wire extendinglongitudinally through a portion of the catheter body.
 38. The method ofclaim 24, wherein moving a wire extending longitudinally through aportion of the catheter body comprises moving the wire in radialdirections.
 39. The method of claim 24, wherein moving a wire extendinglongitudinally through a portion of the catheter body comprises movingthe wire in an axial direction.
 40. The method of claim 24, whereinmoving a wire extending longitudinally through a portion of the catheterbody comprises moving the wire with an ultrasound transducer.
 41. Themethod of claim 19, wherein moving the heat exchange surface comprisesrotating a wire which extends longitudinally through at least a portionof the catheter body.
 42. The method of claim 28, wherein at least aportion of the wire has a non-symmetrical cross-section.
 43. The methodof claim 28, wherein at least a portion of the wire has a radialprotrusion extending therefrom.
 44. The method of claim 28, wherein aportion of the wire in angled in a radial direction.
 45. The method ofclaim 32, wherein circulating heat exchange fluid across one side of theheat exchange surface comprises passing the heat exchange fluid througha balloon.
 46. The method of claim 32, wherein passing the heat exchangefluid through a balloon comprises simultaneously passing the fluidthrough a plurality of lobes in a multi-lobbed balloon.
 47. An improvedcatheter system for heating or cooling the body, the improvementcomprising: a multi-lobed heat exchange balloon; and a mechanism formoving the heat exchange balloon, thereby disrupting fluid flow over aheat exchange surface of the balloon.